Question

Is it true that under certain conditions, $Mg$ can reduce $A{l}_2{O}_3$and $Al$ can reduce $MgO$? What are those conditions?

Answer 1

Ellingham diagram
Ellingham diagram is used to predict thermodynamic feasibility of reduction of oxides of one metal by another metal. Any metal can reduce the oxides of other metals that are located above it in the Ellingham diagram.


Condition where $Mg$ can reduce $A{l}_2{O}_{3}andAl$ can reduce $MgO$

At the point of intersection of the $A{l}_2{O}_3$ and $MgO$ curves (marked "A" in diagram), the ${\Delta }_r{G}^{\Theta }$ becomes zero

Hence, below this point $(A,{1350}^{\circ }CMg$ can reduce $A{l}_2{O}_3$ . Above point A, $Al$ can reduce $MgO$.

Hence it is true, under certain conditions, $Mg$ can reduce $A{l}_2{O}_3\text{and}Al\text{can reduce}Mgo$.